Charcoal

It’s hard to comprehend how pivotal a role charcoal has played in the development of our history: not only did it single-handedly fuel the Industrial Revolution, but also – in a recent twist – might be the solution to reversing the environmental wreckage that resulted from this very revolution.

More than simply the stuff with which to kick off a backyard barbecue, charcoal is regarded by some as the oldest material synthesized by humans. Early traces were found in European cave paintings dating back roughly 32,000 years. In 35,000 BC, charcoal was used throughout Europe and Asia as an important fuel source. By 2,000 BC, it ushered in the Bronze Age, fueling furnaces and forges, and burning hotter and cleaner than wood.

Charcoal detail. (Image via Abdillah Wicaksono at Flickr)

For the most part, charcoal is produced through slow pyrolysis, which involves the heating of wood in the absence of oxygen – in other words, the distillation of wood to its carbon content. Charcoal can be fabricated through a variety of methods. The process is so precise, in fact, that charcoal production has historically been entrusted to colliers –professional charcoal burners in the 13th-century who lived alone in small huts, tending to their slow fires as necessary.

In ancient Rome, charcoal was mixed into tar for caulking and embalming – and used for everything from dyes to construction. Across several centuries and just as many continents, the material is found in the production of glass, gunpowder and in the smelting and shaping of metals. Blacksmiths employed charcoal as their primary burn material since the profession itself was founded, forging agricultural tools, horseshoes and other everyday essentials thanks to its superior porosity – allowing for the temperature at which it burns to be more easily moderated.

Charcoal traders on the Bongo-Bolgatanga road to Ghana, West Africa. They use tree species that can be coppiced, meaning the charcoal and fuel wood are sustainably produced – a rarity in the region. (Image via Treeaid on Flickr)

However, the widespread popularity of charcoal as a fuel has also led to massive destruction. At a sub-industrial level, charcoal production is one of the leading causes of deforestation, and is therefore illegal in many countries. Some of the worst damage has occurred in the Democratic Republic of Congo, Zambia, Malawi and Brazil.

Ironically, charcoal has been revered as a powerful and natural filter since the Romans, purifying air, water and soil once “activated” (treated with oxygen). The field of medicine has long used charcoal as an effective absorbing agent for poisons and other gastrointestinal issues. Its absorbent qualities are helpful in the home, too, efficiently removing smells in refrigerators, closets and other enclosed spaces. As an alkalizer, charcoal is an excellent water purifier, both softening and improving the flavor of water.

On a larger scale, a new agricultural use for charcoal was recently discovered. “Terra preta” (“black earth”) soils in the Amazon show that the use of “biochar” by pre-Columbian cultures resulted in improved, carbon-rich soil. Biochar, the term used for charcoal used horticulturally, has been shown to increase soil fertility of acidic soils, increase crop yields and even result in improved pest resistance. Biochar has also been shown to improve water quality by increasing the soil’s ability to retain nutrients – therefore decreasing groundwater pollution (especially if agrochemicals have been used on the crops). Biochar is now under consideration as a method of carbon sequestration, as it has the potential to help mitigate climate change through the production of negative carbon dioxide emissions. The carbon contained in biochar resists degradation and can hold carbon in soils for hundreds of years.

Whether fueling the irons of blacksmiths, blackening the hands of artists or purifying the water you drink, charcoal continues to ignite our imaginations as a powerful and versatile material.

Top image by Mrs Scarborough. Licensed under Public domain via Wikimedia Commons.